The growth in sales of Irish whiskey in the US alone will lead to a significant expansion in Ireland’s native malting barley acreage.
A recent edition of the Tillage Edge podcast reviewed the question-and-answer sessions that were key dynamics within the recent Teagasc malting barley webinar.
Eoin Lyons, Teagasc/Boortmalt joint programme malting barley advisor, was asked about the relevance of growing cover crops as part of a malting barley rotation.
He explained:
“A catch crop of oats and mustards will work as a later drilling crop. We would have seen that out on farm.
“Definitely, mustard would have gone in the mid-September period.
“Mustard plots alone have the capacity to take up to 23kg of soil nitrogen per hectare.
“In contrast, a mix of leafy turnip and forage rape will only take up 10kg.
“So, there is definitely potential to look at mustard as a later-sown cover crop.”
Teagasc’s Dr. Richie Hackett addressed the issue of developing a growth area index (GAI) for catch crops.
He said:
“This work has already been carried out with oilseed rape. Where catch crops are concerned, it gets a bit more complicated, where mixtures are involved.
“Work, carried out abroad, has been undertaken to estimate how much nitrogen is in a crop and how much is likely to become available.
“But they are all quite complicated and exactly how they work is unclear. The reality is that more work needs to be carried out into the development of relevant GAIs.”
Hackett also addressed the issue of crop nitrogen availability if malting barley is grown in land previously treated with animal manures, or in a freshly ploughed grass ley.
He said:
“The fresh ground scenario is particularly difficult as the grower will not know how much nitrogen will become available over the growing season.
“Measuring the nitrogen in the soil is only half the story. The unknown is predicting the impact of the decaying vegetation.
“Assessing the impact of organic manures is a little bit easier. Where pig slurry is concerned, you would expect 50% of the nitrogen to become available.
“But it is important to have the slurry tested beforehand.”
Hackett advised not to be growing distilling barley varieties in fresh ground, adding:
“Growers would be stacking the odds against themselves from the start by taking this approach.”
Co. Laois grower, David Walsh discussed the impact of catch crops.
He said:
“We have sheep grazing our cover crops at the present time. The will be taken off soon and the ploughing undertaken within days.
“We have estimated that there is approximately 45kg/ha of nitrogen in total within the crops.
“If we are lucky, 15kg of this will be made available to the following barley crop.”